Re: enlargement factor... (was Re: modifying scanner)

From: Michael Healy ^lt;[email protected]>
Date: 11/19/04-10:13:18 AM Z
Message-id: <419DB92E.17797.554D42D@localhost>

Susan, here's a little math for you: If you scanned a 4x5 at 2400 ppi, that's some 9600
pixels across the 4 inches. Stretching these to 20x24 would make 9600/20, or about 480
ppi. That's assuming you can scan at 2400 ppi (or higher). How your process will look at
that level of resolution is one thing you should check out. The simplest way would be to
scan a 4x5, and then make a digitial neg of a mere slice of it. That way you have a
sample neg, but haven't dedicated a large piece of paper. This also would tell you
whether you can live with the way pinhole enlarges to that size.

I'm with Loris on this one, though. An enlarged pinhole image simply is not going to look
like something Ansel Adams shot in Yosemite. OTOH, these can be a lot sharper than
you would think. I have done contact argyrotypes and cyanotypes using 4x5 and 8x10
HP5, which I think is horribly grainy. (I have used it for tests so I can use HP5 in a 7x17,
where it's one of the only available films.) was quite surprised to find that its grain wasn't
even noticable. Of course, these weren't enlargements; but going from 4x5 to 20x24
doesn't involve that much enlargement anyhow.

Personally, I would pursue now this with the 4x5 you've already got, and run a few test
enlargements. Who knows, maybe you'll find that your "problem" doesn't even need a
solution. Altho I would add that I've been using the 8x10 (including pinhole) for the past
12-15 months, and it is hard to go back to the puny 4x5. Be forewarned. If you turn out
to be one of those people. well, your life will be harder.


On 19 Nov 2004 at 9:40, wrote:

from Loris...
              "Since you're using pinhole cameras, I don't think that
factor is as critical as in non-pinhole work. 4x5 pinhole images can
be pretty sharp (more so after a little bit treatment in image
editing software)."

    I'm not married to the 8x10 negative idea. I was only going that
because i thought i might need that size neg to get my final image
size as large as i want. But maybe 4x5 negs will work for me?

    If i stick with 4x5 negs, i can either use my pinhole or my view
 Maybe i'm stressing too much about the enlargement issue. I just
 want to
be sure that, as i'm setting up for this process ( film negative to
scanner to digital negative to copper plate photogravure ), I can get
to the maximum size my press will accept ( 22" wide). That's not to
say all my prints will be that size... especially in the
beginning.... but i want to have that option.


Susan Daly Voss
lower upstate NY
Received on Fri Nov 19 10:13:41 2004

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